Prevent default event for the removeContact link in order to avoid page reload when jQuery Dialog is openened from clicking on the delete link

Show dt elements on xmppchat-roster only if they have length and they are not already visible to avoid making them all the time visible when they might already be so

- Subscribe event with help of jQuery one instead of delegate, now that
  the rosterView is no longer emptied on every render to avoid
  registring several handlers of remove action, which meant you had to
  click 4 times for the jQuery Dialog to go away
- Remove the element from the rosterView when the remove event is
  triggered on the model which removes just that item instead of
  emptying the list and appending the remaining models again

Fixed a bug where controlbox wasn't available on xmppchat.chatboxesview, instead pass the removal of the model to rosterview.model

- Show the xmppchat-roster only after all of the items have been added
  from first run of rosterHandler
- Resort the items only when the presence has changed and not when the
  resource attribute has changed

- Pass an option object to addRosterItem which can contains information about
  the object catched in the rosterHandler.
  In this case I am marking the last item available in the roster of the
  person for which this handler is triggered

Removed rendering of rosterview since I've added check to render only with passed item and the result is the same without the rendering

- Fixed function has inconsistent return points by always specifying
  returns instead of returning only on condition
- Set room-jid as data-room-jid attribute to validate html5
- Added missing semicolon

Set modifications of model attributes only if the item received from the rosterHandler has different options

Conflicts:
	converse.js

Also other backports from production.

Feature: added "Connecting to chat ..." info

- Feature: added spining image and "Connecting to chat ..." info under chat panel
  when the user is not (yet) binded to the jabber server
  [alecghica]

Pass item to render method of RosterView instead of looping over each item on every render call, Inverted visibility logic for contact titles in order to avoid multiple show and hide

Moved assignment of template for RosterView out of the render method to avoid calling empty and readding items everytime the render method is called

This has fixed some IE8 errors while parsing the presence stanza

So that it doesn't depend on it's element already being in the DOM

Also added a new jasmine spec for this as well as jquery.tinysort to do the
sorting.

Also add flush method to converse.js (used in ClientStorage tests)